The present invention relates in general to a wireless power transmission system. One particular aspect of the present invention relates to a remote power transmission system for vehicles.
There have been numerous attempts and initiatives established for next generation land based vehicles. Federal and local governments have placed limits on emissions as well as set standards for fuel consumption. Some programs have set goals for vehicle mileage of 80 miles per gallon and greatly reduced vehicle emissions based on today""s standards. Even with recapture of regenerative braking energy, a hybrid electric/internal combustion vehicle will be hard pressed to meet these goals.
One of the major causes of smog today is the use of city buses for public transportation. Diesel and gasoline driven buses spew out tons of pollutants daily. Utilization of buses powered by electricity would eliminate this source of pollution from our cities. To date, the most reliable electric source has been overhead tethered line or on-ground tracks. But these greatly reduce the convenience of route changes and are at the mercy of small traffic pattern changes which can cause traffic tie-ups. The ideal electric bus would have a completely mobile energy source, such as a battery pack. But the limited range of a battery-powered vehicle has diminished public acceptance of such vehicles.
In large cities a single battery pack, consisting of several standard 12- or 24-volt batteries, provides power only for driving an all-electric bus one or two route cycles. The vehicle must then be pulled out of service for either an expensive battery pack replacement to allow the discharged battery unit time to be recharged while the vehicle is put back in service immediately with a fresh battery pack; or the vehicle must be taken completely out of service while the battery unit is being charged on the vehicle. Recharging the battery pack can be a four-or five-hour process. Therefore an all-electric, completely mobile city bus service is cumbersome to run and maintain, difficult to keep on schedule and expensive to operate.
Originally, a wireless power transmission system was proposed to augment the existing system of electrical conductors that are used to move large quantities of electrical power over long distances. Later, systems were proposed to convert large quantities of solar energy into an energy beam that could be transmitted from outer space to the surface of the earth through satellite transmissions. Once on earth the energy beam would be converted back to a usable energy form that would be pumped into the existing electrical energy distribution grid.
See for instance U.S. Pat. Nos. 3,114,517; 3,781,647; and 3,174,705. Several transmission frequencies of the energy spectrum have been considered to minimize the energy loss from the beam as it travels through the atmosphere, including radio frequency (RF), laser, and optical frequency (OF). For the RF energy beam, atmospheric attenuation is a minimum up to 4 GHz even during a heavy rainstorm. Other windows of transmission exist at 35 GHz and 94 GHz. Systems designed to operate at these relatively high frequencies have the added advantage of operating at smaller apertures wherein the transmitting antenna and the receiving antenna can be smaller. Such systems have been considered for transmission of energy from satellites in a low earth orbit or geosynchronous orbit to the surface of the earth, a distance of many kilometers. Transmitting from space to the surface of the earth greatly diminishes laser based energy beam capabilities due to the long distances the laser beam must travel in the earth""s atmosphere.
A wireless remote system capable of transmitting energy distances of 100 to 500 meters is needed. At these relatively short distances, even taking into account additional power requirements for attenuation in the earth""s atmosphere, many more RF bands become available. Energy transmission via a laser beam also becomes viable.
Laser energy beam transmission has the additional advantage of requiring relatively small transmitting and receiving antennae.
Briefly stated, the invention in simplified form comprises a power transmission unit and a power receiver system. In some embodiments there are a plurality of power transmission units, each interconnected to a power source such as, for instance, the existing electrical power transmission grid. Each power transmission unit or xe2x80x9cPTUxe2x80x9d includes a power transmitter selectively activatable between the on and off condition. In the on condition, the power transmitter transforms energy from the power source into a directionally transmitted wireless power beam. The power transmission unit also preferably comprises a communication device for receiving a communication signal and a power unit controller operably connected to both the communication device and power transmitter. The power unit controller device is preferably a logic type device incorporating microprocessors and functions to control the overall operation of the power transmission unit. In other embodiments the power transmission unit includes safety devices, signal locating and tracking capabilities as well as a device or devices to change the focus and/or orientation of the directional power beam transmitted by the power transmitter.
The power receiver system is preferably comprised of a number of operably interconnected components. The power receiver system will include an energy receptor, such as an antenna, receptor/converter or combination receiver/antenna (rectenna). The energy receptor receives the power beam transmitted from the power transmitter. Each system will also comprise an energy converter, which converts the energy received by the receptor to a form capable of storage in an energy storage device. A power usage monitor monitors the energy level in the energy storage device and preferably the energy being expended and energy being received by the energy receiving means. A transmitter/locator or xe2x80x9ctranslocatorxe2x80x9d is operably connected to the power usage monitor. The translocator functions to transmit a translocator signal from a translocator antenna.
In some embodiments the power receiver system is incorporated into a vehicle. It should be understood that the term xe2x80x9cvehiclexe2x80x9d is meant to encompass any and all vehicle types unless specifically limited. A surface vehicle may similarly be of any type for use on or near any surface such as, for example, boats, cars, trucks, golf carts, hovercraft or amusement park rides. Each vehicle would have many of the attributes of presently existing vehicles. Passenger cars for instance would typically include well known provisions for steering, speed control, suspension, braking, heating, ventilation and air-conditioning, etc. The motor for the vehicle could be any type which is able to utilize the energy received and/or stored by the vehicle, as later described.
In use of a preferred form of the invention, the vehicle would travel along existing routes; cars for instance would travel along existing roads. Each vehicle is independent, relying on its own motor for motive power and powering the motor with energy received from the power transmitter or from the energy storage device contained on board the vehicle. The power usage monitor constantly checks the amount of energy contained within the energy storage device as well as the amount and rate at which energy is being withdrawn from the energy storage device. When the level of energy in the energy storage device falls below a predetermined level, the power usage monitor activates the translocator to start transmission of a vehicle communication signal.
The vehicle communication signal is received by a power unit controller via the power unit communication device. The power unit controller xe2x80x9cinterpretsxe2x80x9d the vehicle communication signal as a request for power transmission and locates the source of the vehicle communication signal, which is, of course, the location of the vehicle, or more preferably, the location of the vehicle energy receptor. Once the vehicle energy receptor is located, the power unit controller orients the power transmitter and initiates broadcast of the directional power beam to the vehicle receptor. Naturally, if the vehicle is moving, the power transmission unit continues to track the vehicle location via the vehicle communication signal and adjust the power transmitter so that the directional power beam remains aligned with the vehicle energy receptor. When the vehicle has received sufficient energy, the translocator terminates the vehicle communication signal, causing the power unit controller to cease power beam transmission from the power transmitter.
In some embodiments the power usage monitor tracks the energy received by the energy receptor. This information may be part of the communication signal which is transmitted from the power receiver system to the power transmission unit. If the communication signal fails to acknowledge the receipt of power from the power beam, the power unit controller can actuate the power transmitter to the off condition, terminating transmission of the power beam. This acts as a fail-safe should the power beam be interrupted or should the power beam and energy receptor become misaligned. Given the short distance between the power transmission unit and energy receptor and the fact that the power beam and communication signal travel at the speed of light, communication between the power receiver system and power transmission unit is almost instantaneous and takes place before the energy receptor has moved any significant distance.
In another aspect of the invention the power beam comprises a series of pulses or energy packets, receipt of each or some number of which must be acknowledged by the power receiver system in a communication signal before the next pulse or pulses are transmitted by the power transmitter to the energy receptor.
In a further aspect of the invention the communication signal comprises a data stream transferring information to the power unit controller. In this way, each power receiver system may be uniquely identified so that a power transmission unit receiving multiple communication signals can locate and track an individual energy receptor.
In another embodiment the vehicle also includes a translocator energy unit operably connected to the power receiver system. The translocator energy unit is a logic device having a user determinable number of energy credits. The vehicle communication signal, as part of the data stream, may include the number of energy credits contained on the translocator energy unit. As a power transmission unit transmits the power beam to the vehicle, the energy credits are electronically exchanged for quantities of power transmitted. When the energy credits in the translocator energy unit are depleted the translocator signal is terminated and the power unit controller stops transmission of the power beam. No further power transmission will be received by that vehicle until the vehicle operator has replenished the energy credits contained in the translocator energy unit.
In a further embodiment the power transmission unit communication device may also comprise a transmitter and the translocator may comprise a receiver. In this manner, when the communication signal is received by the power transmission unit, a power unit communication signal can be returned to the translocator antenna, establishing two-way communication between the power transmission unit and the power receiver system. In this embodiment, transmission of the power beam is initiated only after the two way communication has been established.
An object of the invention is to provide a new and improved wireless power transmission system and method.
Another object of the invention is to provide a new and improved wireless power transmission system and method, which is especially suited for use in short range, urban environments.
A further object of the invention is to provide a system and method for receiving wireless energy and converting the received energy to a different form.
Still another object of the invention is to provide an energy safety system and method.
A still further object of the invention is to provide a hybrid energy storage device.